Perceptual categorization of cat and dog silhouettes by 3- to 4month-old infants

Given evidence that silhouette information can be used by adults to form categorical rep-resentations at the basic level, four experiments utilizing the familiarization-novelty prefer-ence procedure were performed to examine whether 3- and 4-month-old infants could form categorical representations for cats versus dogs from the perceptual information available in silhouettes (e.g., global shape and external outline). Experiments 1 and 2 showed that infants could form individuated categorical representations for cat and dog silhouettes, whereas Experiments 3 and 4 revealed that infants could use silhouette information from the head, but not the body, to categorically separate the two species. These results indicate that general shape or external contour information that is centered about the head is sufficient for young infants to form individuated categorical representations for cats and dogs. The data thus pro-vide information regarding the nature of the perceptual information that can be used by infants to form category representations for individual animal species and are discussed in terms of domain-general versus domain-specific processing accounts. © 2001 Academic Press Key Words: categorization; visual cognition; perceptual development; cognitive devel-opment. Perceptual categorization refers to the recognition of discriminably different entities as members of the same category based on some internal representation of the category (e.g., Edelman, 1987). In this article, the term categorical repre-sentation is used to describe this internal representation. When and how categor-ical representations are initially formed, elaborated, integrated with other knowl